Polyimides of substituted phthalic anhydride



United States Patent "i 3,531,436

Patented Sept. 29, 1970 may be the acid halide of trimellitic anhydride, a hy- 3,531,436 droxyepoxy adduct of trimellitic anhydride, and an amide- POLYIMIDES 0F SUBSTITUTED amine adduct of trimellitic anhydride. Unsubstituted tri- PHTHALIC ANHYDRIDE mellitic anh d f y n e 1s 0 muted value for direct polymeri- 1123 2 332 gi g fg g gg g ggg353 2E: zation to the polyimide and the invention will further be signers to Borden Inc. New York, NY a c0rp0ra 5 described in connection with substituted trimellitic antion of New Jersey hydride. Where an amide-amine adduct is used as the No Drawing. Continuation of application Ser. N monomeric component, additional diamine is not required 493,237, Oct. 5, 15765. This application Apr. 21, for polymerization. Where the acid halide is used, an acid 1969, Ser. N0i 8t18%0%08 20/32 10 acceptor is added to advantage to the reaction medium.

ll g Pol merization is enerall ar (1 out in a olv nt f r us. Cl. 26047 7 Claims y g y c m s e o the starting materials which may also be a solvent for the final polymer.

Conventional solvents are used in the polymerization ABSTRACT OF THE DISCLOSURE which are nonreactive with the reactants. Examples of the The present invention relates to imides and polyimides solvent include benzene and like aromatic and alkaromatic having the general structural formula solvents, dimethylformamide and dimethylacetamide.

o(o)0 3(0)T -R'R"O(O) 0(0) NHzL-RRO(0)C(O)J wherein: When an acid halide is used, it is reacted with a diamine I of the structural formula NH RNH under elevated tem- (1) R is a hydrocarbon moiety; peratures as between 50 -330 C. (R is the same as above R 15 Selected from the group conslstmg of defined.) The reaction may take as long as 24 hours to complete, the rate being reduced with increased tempera- OH ture.

When an epoxy adduct is a comonomer, it is polymwhflFm A 15 the Y Y molety of a mono erized with a diamine of the same structural formula hydnc alcohol contammg at least one epoxy group shown above, under elevated temperatures as in the range and and of 50 330 c.

(3) n is an integer up to about Where it is desired to produce the amide-amine mono- 30 meric unit and then polymerize this monomer, starting This is a Streamlined continuation of application materials such as the acid hal ideof trimellitic anhydride No. 493,237 filed Oct 5, 1965 are used to advantage. The halide is reacted with a diamine This invention relates to polymeric imides and more under redufied temperatures as below aPout 9 and particularly to polyimides of phthalic anhydride. Poly- 40 Preferably n e range 0-5 C. The amide-amine adduct imides of this invention have high temperature stability. 13 then auto-Polymenzed to form the polyimide of These polymers are useful as protective coatings on surinvention y reaction under elevated temperaturesfaces which are exposed to elevated temperature during AS Proportions, molar equivalents of the monomeric components are preferred such as to provide a one to one The present invention provides imides and polyimides of addition polymer between the substituted phthalic anphthalic anhydride. The invention comprises a polymer hydride and the diamine. having the following general structural formula: As to materials, an acid halide of trimellitic anhydride,

o(o)o wherein R' is a hydrocarbon or substituted hydrocarbon represented by the following structural formula (X being examples of which include aryl, alkaryl, oxyaryl, and chloride, bromide or iodide):

alkyl; R is selected from the group consisting of (a), (5(0))? -NH-(1|\)O wherein A is selected from the group consisting of satu- \C(O) rated and unsaturated aliphatic, cycloaliphatic, aromatic C (O) O and heterocyclic hydrocarbon moieties which moieties may further be substituted with noninterfering substituents such as halogen atoms, and (b), -NH; and n is an is the basic starting reactant. integer up to about 100. The polyimides may readily be The acid halide anhydride is made as by reaction of prepared from substituted phthalic anhydride and a di trimellitic anhydride with halogenating compounds; examine by inducing polymerization under elevated temamples of such known compounds include thionyl chloperatures. ride, phosphorous pentachloride or the corresponding The substituted phthalic anhydride starting materials halide and the like. The acid halide anhydride is further reacted with a diamine and if desired an epoxyalcohol depending upon the type of copolymer or polymer, and reactions desired.

The diamine component, represented by the structural formula, NH RNH should have at least two primary amino groups therein and may have additional amino groups in the structure to favor cross-linking. The anhydride ring is opened by a primary amino nitrogen to form the imido linkage. Polymerization therefore requires one such primary amino group for each anhydride ring. The reaction with the halide or epoxy portion of said anhydride may be either through a primary or secondary amino group. .Although a diamine having one primary and one secondary group could theoretically be used, it has been found that in order to achieve the relatively high degree of polymerization as up to about 100 units, and cross-linking of the instant invention, it is preferable to use an amine having at least two primary amino groups therein. A diamine containing at least two primary amino groups provides the additional reactive hydrogen available for cross-linking of the polymer and probable prevention of termination of the polymer chain. Chain termination probability would be enhanced if a diamine having only one primary and one secondary amino group were used, and the primary amino group was reacted with the halide or epoxy moiety. This would thereby leave unreacted the anhydride ring, there being a lack of available primary amino groups. Primary amino diamines eliminate the possibility of this occurring.

The primary amino diamines may have noninterfering substituent groups within their structure such as oxy, halide and sulfonyl groups. R may be aryl such as phenyl and biphenyl; alkaryl such as C -C alkyl diphenyl; oxyaryl such as oxy diphenyl; alkyl such as C -C alkyl; and cycloaliphatic such as C -C alkyl substituted C -C cycloaliphatic moieties. Examples of the preferred primary amino diamines include:

4,4-diamino diphenylmethane (methylene dianiline), 4,4'-diamino diphenyl ether (oxydianiline), 1,6-hexane diamine, 1,2-ethylene diamine and l-methyl, l-amino, 4-(2-amino)propyl cyclohexane.

As to the hydroxyepoxy reactant, it comprises those monohydric alcohols possessing at least one epoxy group, i.e., a

I I C C group. These alcohols may be aliphatic, cycloaliphatic, aromatic or heterocyclic and may be saturated and unsaturated and substituted with noninterfering substituents such as halogen atoms and contains between threefifteen carbon atoms. Examples of these epoxy substituted alcohols include epoxyalkanols, epoxyalkoxyalkanols, epoxyalkenols, epoxyalkoxyalkenols, and cyclo derivatives thereof. Examples of these epoxyalcohols include: 2,3-epoxypropanol (glycidol), 3,4-epoxybutanol, 2,3-epoxyhexanol, epoxidized octadecadienol, 3,4-epoxydihydropyran 5 propanol, 2,3 dimethyl-4,5-epoxyoctanol, Z-methoxy 4,5 epoxyoctanol, 3,4-epoxy-5- chlorocyclohexanol, 2,3 epoxypropoxypropanol, 2,3 epoxypropoxyhexanol, 2,3 epoxypropoxy 2,3 dihydro heptanol, 2-3-epoxydodecanol, 4-chloro-5,6-epoxydodecanol, 3,4 epoxydodecanol, 2,3-epoxycyclohexanol, 2,3- epoxy-S-octanol, 2,3-epoxy-6-dodecanol, 2,3 epoxypropoxy-S-octenol, 2,3-epoxypropoxy 4 cyclohexanol, and the like.

Particularly preferred are the r nonoepoxy substituted alkanols containing between 3-8'carbon atoms and having the epoxy group in the terminal position. Within this group 2,3-alkanol such as 2,3-epoxypropanol are preferred.

The following is a brief description of the process steps.

(1) Preparation of acid halide of phthalic anhydride.Trimellitic anhydride and excess thionyl chloride are heated to reflux until the reaction is substantially complete. The product is collected by fractional distillation. It is believed to have the following structural formula:

A molar excess of the chloride is used, as about 4 moles of chloride to 1 mole of the anhydride.

(2) Preparation of trimellitic epoxy ester.Trimellitic anhydride mono acid halide (preferably the chloride) is dissolved in a solvent, such as benzene, and added slowly to a precooled solution of a hydroxyepoxy, acid acceptor and solvent. The reaction is maintained at the reduced temperature, as in the range of 0-5 C. After the reaction is essentially complete, the amine salt is separated and the epoxy ester is concentrated from the solvent. Approximately equal molar proportions of the halide, the epoxy, and the acid-acceptor are used. In an alternate procedure, acid acceptor and acid halide are added simultaneously to the epoxyalcohol at 05 C.

(3) Preparation of amide-amine adduct of trimellitic anhydride.Trimellitic anhydride mono acid halide (preferably the chloride) is dissolved in a solvent, such as benzene, and added slowly to a precooled solution of the diamine, acid-acceptor and solvent. The reaction is maintained at the reduced temperature, as in the range of 05 C. After the reaction is essentially complete, the acid portion is separated and the adduct concentrated. Approximately equal molar proportions of the halide and diamine are used. The acid-acceptor is used in molar proportion approximately equal to its acid accepting value, i.e., equal molar proportions if triethylamine is used, however, onehalf the molar quantity if sodium carbonate is the acid acceptor.

If an unsymmetrical diamine is used, as for example,

(l-methyl, l-amino, 4-(2-amino)propylcyclohexane) the resulting amide-amine adduct is a combination of the two possible products, whereas if a symmetrical diamine, such (oxydianiline) is used, the amide-amine adduct is uniform.

In the examples that follow and elsewhere herein, proportions are expressed as parts by Weight unless specifically stated to the contrary.

EXAMPLE 1 (Copolymerization of acid halide and diamine) with cold methanol and dried in a vacuum oven to con- EXAMPLE 4 Stant Weight The product The polymeric materials made as in Examples 1, 2 and 3 are prepared as therein described except that the d 15 E amine therein used is replaced separately and in turn by -NH-ONH2 5 the diamines herein previously disclosed. 0

\ EXAMPLE 5 ii The copolymer of Example 2 is made as therein de- 0 (8) 10 scribed except that the epoxy adduct of the acid halide Was a y Solid, melting Point greater than therein used is replaced separately and in turn by the Pefeeht nitrogen: Found, hydroxyepoxy compounds herein previously disclosed.

The Product y be POIYmeTiZed directly ill dimethyl' It will be understood that it is intended to cover all formamide give a dimellhylformamide Solution of the changes and modifications of the examples of the inven- Polyimide which can he used to protectively coat aTlieleS tion herein chosen for the purpose of illustration which prep film-S therefrom do not constitute departures from the spirit and scope EXAMPLE 2 of the invention.

What is claimed is:

(Copolymenzatlon of epoxy ester and dlamme) 1. A polyimide having the general structural formula C(O)O l (iJ(O)N RRC (O) C(Ov NHz-R' "-o(o o(o l L n Liquified methylenedianiline (2.0 g.) was thoroughly mixed with monoglycidyl trimellitic anhydride (2.5 g.) wherein: and the mixture heated for 3 hours at 250 C. in a Woods (a) R is a hydrocarbon selected from the group conmetal bath. sisting of divalent aryl, alkaryl, oxyaryl, and alkyl This reaction can also be carried out in dimethylmoieties; formamide to give the polymer in solution. (b) R" is Polymer 0 ll 0 0H F 1 Q Q COCHz-CHCHz-RNH 0H2- -NH2 0 J \C ll 0 (9) wherein R is t? C 0 OH 1 1 iooH2 EH-c1n I! O n Analysis.Calcd. for C H O N (percent): C, 70.1; I H, 4.67. Found (percent): C, 69.49; H, 4.19.

EXAMPLE 3 \OH) (Polymerization of amide-amine adduct of trimellitic Wher.em A Is the hyfhjmrbm molety of a monoanhydride) hydrrc alcohol containing at least one epoxy group of the formula The intermediate adduct was obtained by the procedure described in Example 1 except that the oxydianiline was O replaced by 1,6-hexandiamine (11.6 g.). The adduct (11 g.) was obtained as pale yellow crystals which softened at 130 0. and melted at 1so 210 0. After heating for and 2 hours at 170-180 C. in an oil bath, the product was (0) n 13 an Integer havmg a Value of from 1 P about 100. a transparent brown Sohd' 2. The polyimide of claim 1 wherein:

0 E (a) R is selected from the group consisting of phenyl, H 0 f biphenyl, C -C alkyl diphenyl, oxydiphenyl, C C c H O 2)e z alkyl, and C -C alkyl substituted C -C cycloali- O NH(CH2)6N phatic divalent moieties: 0 b RI ll ls o 0 -NH-Aol n I OH Heating the dimethylformamide solution without isolating the product gave the polyimide in solution. and A is the hydrocarbon moiety of a monohydric 7 alcohol containing at least one epoxy group of the formula said alcohol being selected from the group consisting of 2,3-epoxypropanol, 3,4-epoxybutanol, 2,3-epoxyhexanol, epoxidized octadecadienol, 2,3-dimethyl-4,5- epoxyoctanol, 2 methoxy-4,S-epoxyoctanol, 3,4- epoxy 5 chlorocyclohexanol, 2,3-epoxypropoxypropanol, 2,3-epoxypropyhexanol, 2,3-epoxydodecanol, 4 chloro-5,6-epoxydodecanol, 3,4-epoxydodecanol, 2,3 epoxycyclohexanol, 2,3 epoxy-S-octanol, 2,3- ep0xy-6-dodecanol, 2,3-epoxypropoXy-5-octenol and 2,3-epoxypropoxy-4-cyclohexanol.

3. The polyimide of claim 2 wherein R' is 1,6-hexylene and the other variables are as therein defined.

4. The polyimide of claim 2 wherein R is an oxydiphenyl divalent moiety and the other variables are as therein defined.

5. The polyirnide of claim 2 wherein R" is A is the hydrocarbon moiety of 2,3-epoxypropanol and the other variables are as therein defined.

6. The polyimide of claim 2 wherein R is a methylene diphenyl divalent moiety and the other variables are as therein defined.

7. The polyirnide of claim 4 wherein R" is A is the hydrocarbon moiety of 2,3-epoxypropanol and the other variables are as therein defined.

References Cited UNITED STATES RATENTS,

7/1966 Lavin et al. 260.78

FOREIGN PATENTS 7/1945 Great Britain.

'U.S. Cl. X.R. 

